Electroactive ballistic protection system

ABSTRACT

A ballistic protection system combines electrical storage and/or electrical generation features, including at least one layer of material which provides ballistic protection and at least one layer of material which is electrically active.

FIELD OF THE INVENTION

This invention relates to the field of rechargeable battery systems, energy harvesting and ballistic protection systems primarily used for dismounted soldiers and police officers.

BACKGROUND OF THE INVENTION

Ballistic protection for a variety of applications generally takes one of two approaches to preventing injury from projectiles such as bullets and shrapnel. The oldest approach focuses on stopping the projectile and dissipating the force of the projectile over a wide enough area that blunt trauma and puncture is minimized. Materials such as Kevlar®, fibreglass and steel have been used for this purpose. When struck by a projectile, the projectile flattens against the ballistic material or is captured by it.

A more modern approach to ballistic protection is the use of ceramics and other similar materials to break the projectile into smaller parts, effectively using the energy of the projectile to destroy itself. As a result, the energy of the projectile can be dissipated over a smaller area, and blunt trauma and penetration is reduced. This is particularly effective with armour piercing bullets which utilize a hard tip to penetrate conventional armour.

Hybrid approaches utilizing laminated layers of both types of ballistic protection have been proposed which allow construction of thinner and lighter plates. In some cases these are coupled with soft gel or rubber materials to increase comfort levels and further reduce blunt force trauma.

Variable durometer materials may be coupled with the ballistic armour which allow flexibility to be added to the plates. These variable durometer materials have a low durometer (are soft) in normal use and therefore can adapt to the body. When exposed to a rapid change in force, such as being struck by a projectile, the material stiffens, the durometer increases significantly, allowing the force of the projectile to be absorbed and dissipated over an even larger area.

Battery systems are often constructed from laminated layers of material which is electrically active. This may be accomplished by the use of chemical compounds such as lithium, cobalt, nickel, cadmium, magnesium and other materials. Electricity collection materials such as carbon, aluminum and copper are also included and form part of the overall structure. Most batteries also include an insulating separator material that is located between the positive and negative electrodes to prevent short circuiting, and the batteries may include one or more outer housings to hold the electrically active materials, such housings may be composed of steel, aluminum, plastic, foils, or a combination of materials.

Energy harvesting systems based on movement and heat can also be constructed using a multi-layered approach. For example, piezoelectric ceramics, similar to the ceramics used in armour, will generate an electrical charge when flexed, struck or stretched. Laminating these ceramics with conductive electricity collection materials allows energy to be harvested from kinetic movement. In a similar fashion, dopants can be added to fabric, ceramics, or other materials to produce a Seebeck effect, whereby the temperature difference across the plates will generate electricity. Applying many layers of material tends to amplify the Seebeck effect, producing significant energy through the normal temperature difference between the soldiers body and the ambient environment.

Armour is generally heavy, bulky and expensive.

Batteries are generally heavy, bulky and expensive.

Energy harvesters are generally heavy, bulky and expensive.

Soldiers often face the challenge of carrying both armour and batteries into dangerous situations. In most cases it is fair to say that a soldier can never have enough protection, and the need for portable power is also increasing as more electronic systems such as computers, radios and global positioning systems are added to the soldier's load. Yet the ability of a soldier to carry their equipment, armour and batteries is limited, compromises of what the soldier is able to carry may result in the amount of armour worn being reduced, or even eliminated, in favour of carrying more batteries or other equipment.

There is a need for improved ballistic armour that will be multi-functional by including energy harvesting and/or energy storage which provides an overall size and weight reduction for soldiers and others who require both ballistic protection and power.

SUMMARY OF THE INVENTION

The system is designed to improve the safety of soldiers by allowing them to carry more energy to power equipment while preserving or enhancing their ballistic armour protection without increasing weight or decreasing soldier mobility.

The preferred embodiment of the invention includes multiple layers of material where each layer may perform one or more functions. By combining multiple functions into each layer, the overall volumetric and mass efficiency of the system can be improved when compared to the use of single function materials to construct a battery, energy harvester or a ballistic armour plate.

Energy storage is accomplished using layers similar to those used in standard electrochemical batteries. Electrodes, insulators and electrical collector layers which form the battery may all be modified in ways that will increase their ballistic potential. Alternatively, the layers can be used without modification to normal batteries, but the specific properties of the battery layers would be quantified and matched to the armour layers such that impact absorption and energy spreading may still be accomplished by these layers.

Energy harvesting layers based on kinetic motion, temperature differences, solar energy and wireless energy can be accomplished using a variety of materials. Some of these materials are already very similar to those used in ballistic plates. For example, piezoelectric materials commonly used in kinetic energy harvesters based on vibration, are often constructed of doped ceramics. Ceramics are also used in ballistic armour plates to provide a bullet-shredding function. Therefore the use of appropriately doped ceramics can provide the dual function of energy generation and ballistic protection. Some example materials are Lead Zirconate Titanate, Bismuth Sodium titanate and Barium Titanate, all of which can be manufactured in various hardness and with ceramic properties.

The order of layers may also be reversed or may be alternated or may be further combined. For example a battery could be formed in the outer layers of the electro active ballistic protection system. A projectile would be significantly slowed as it passed through these outer layers, which themselves may be enhanced beyond the normal ballistic properties of an off the shelf battery. When the projectile reaches the layers that are specifically focused on ballistic protection, the remaining force of the projectile would be dissipated.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the internal structure of an energy storage component, such as a battery; according to one embodiment of the present invention; and

FIG. 2 shows a ballistic armor solution, according to one embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The system is designed to improve the safety of soldiers by allowing them to carry more energy to power equipment while preserving or enhancing their ballistic armour protection without increasing weight or decreasing soldier mobility.

The preferred embodiment of the invention includes multiple layers of material where each layer may perform one or more functions. By combining multiple functions into each layer, the overall volumetric and mass efficiency of the system can be improved when compared to the use of single function materials to construct a battery, energy harvester or a ballistic armour plate.

Referring to FIG. 1, an energy storage component (100) such as a battery or cell may be fabricated through the use of a positive electrode layer (101) and a negative electrode layer (102), separated by an insulating layer (103). The positive and negative electrode layers would be electrically connected to terminals (104) through conductive layers (105, 106) to allow the soldier to draw or deliver energy into the battery. A complete cell may contain many layers wrapped or stacked together, and a battery may contain many such cells connected together as well as additional power management and control circuitry which is not shown in this simplified construction figure.

In the case of a lithium based battery, the electrodes would normally include carbon and lithium ionic compounds with a plastic insulator material separating the electrodes and aluminum or copper layers to collect and conduct energy to the battery terminals. Each battery (or electrochemical cell) would then be encased in a steel or aluminum shell (107) and a second overall casing (not shown) may be used to hold all of the cells, electronics and other components in a single unified product, which would normally be referred to as simply “a battery”

In a preferred embodiment of the invention, the electrode material would have additional materials added to increase ballistic protection. For example, the addition of micronized ceramics to the electrode materials at a low blend rate of less than 10% would provide increased shredding of a projectile entering the battery layers, yet would only reduce battery capacity by 10% (or the amount approximately equal to the non-electrically active material being added). Certain structures of carbon, such as single walled carbon nanotubes (CNT) can provide dramatic increases in ballistic performance even at blend ratios of less than 1% by weight. Where the ballistic additive is itself electrically active and able to participate in the electrochemical properties of the battery, it is possible to add this ballistic material without significantly altering the capacity of the battery. The high porosity of carbon nanotubes have even been shown to increase battery capacity when used in place of common graphitic carbon.

The insulating layer (103) of the battery is generally very thin, but could be impregnated with an additional weave of strong ballistic fibres such as Aramid or Kevlar, causing the thin insulator material to be reinforced with a web that tends to retain integrity under a penetration event and serves to spread and dissipate the force of a penetrating projectile. The use of boron nitride nanotubes (BNNT), when used in the insulator layer, can allow ionic conduction for the battery to function, while insulating the electrodes from each other. In addition, the ballistic properties of BNNT have been shown to increase ballistic performance of materials at concentrations as low as 0.1% by weight. An added advantage of BNNT is the thermal conduction properties and extremely high temperature survival of this material which can effectively transmit localized heating, increasing overall thermal dissipation of the battery structure. This heat dissipation property is especially critical in preventing thermal runaway for a battery that has been penetrated by a conductive element (such as a bullet) which creates a localized spot of intense heat, capable of igniting the chemicals inside the battery. By dissipating this localized heat and by maintaining insulating properties under such adverse conditions, a BNNT insulator, or insulator made of materials with similar advantages, can improve the ballistic properties of a battery cell without significantly impacting the electrical operation and quality of the battery cell.

Current collecting layers (105, 106) can be made from thicker materials, which would also increase the high-power performance of the battery while providing increased ballistic protection. Alternative alloys of copper, aluminum, or the use of non-traditional conductive materials could also provide an increase in the ballistic properties of the battery layers while maintaining electrical performance of the battery. The use of multi-walled or single-walled carbon nanotubes (SWCNT) in the electrode structure instead of the carbon-graphite normally used, will maintain the electrical performance of the battery while also increasing ballistic performance.

The outer housing of the battery cells can, in a similar fashion, be constructed from thicker materials, or alternative alloys or alternative materials that preserve the performance of the battery, while increasing ballistic performance.

Therefore, in a preferred embodiment of the invention, at least one aspect of the battery layers being composed of: outer housing; current collectors; electrodes; and insulating separator, would be modified to provide increased ballistic performance.

Energy harvesting based on kinetic motion can be accomplished using doped ceramic materials layered between an electrical conductor plate. Other kinetic motion including electricity generating bi-metallic plates, polymers and even microscopic compressible voids can also be considered when constructing layers that target energy generation by kinetic movement.

Energy harvesting may also be accomplished using thermal energy from the body itself. A property known as the Seebeck effect produces electricity through a difference in thermal potential across several different material layers. Electrical conductors are used to gather the electricity from the electrical generation materials. The electrical conductor can be composed of a mesh, and the generation materials can be made sufficiently porous to allow sweat to penetrate and flow through the layers. This increases the thermal potential and therefore the power output while also improving the comfort of the device. As previously highlighted, ballistic armour systems may also be composed of a variety of mesh structures and it is therefore possible to construct mesh structures that provide a dual function of both protection and generation.

Other thermo-electric class generation effects can include, but are not limited to, the Ettingshausen effect, Nernst effect, Peltier effect, Thomson Effect and others. Other kinetic generation effects may include, but are not limited to, electrostatic generation, magnetic motion, Electro active Polymers (EAPs), nanogenerators and vibrational harvesters.

Energy harvesting may also be accomplished through wireless means. Intentional wireless harvesting is generally based on a transmitter and a receiver whereby the transmitter is specifically designed for use with the receiver. This generally results in the highest efficiency and tightest control of the transmission of energy. The receiver portion of this system can therefore also be controlled to allow it to be designed into a variety of materials, shapes and sizes.

Wireless energy harvesting can also take the form of a receiver that collects energy in the form of magnetic, radio-frequency and/or radiation. A receiver antenna is designed to collect energy either at specific frequencies known to be present in the operating environment, for example, 60 Hz radiation from North-American power lines. The antenna may be designed to operate over a very broad band in order to capture energy from a variety of sources including local radio and television stations, cellular phone towers, etc. Antennae constructed from conductive polymers, meshes, and deposited conductive structures can be chosen for their combination of ballistic and electrical properties.

Renewable energy sources such as photovoltaic (solar) power cells may be incorporated into outer layers of the electro active ballistic protection system. Clear plastic materials are often deposited over the surface of solar panels to protect the delicate structures that gather solar energy. The use of ballistic plastics in this outer layer allows a dual function of ballistic armour and solar generation to be incorporated into this energy source. Increasing the thickness or modifying the types of materials used for the electricity collection layers of the renewable energy layers will also increase ballistic protection and further enhance the multi-functional nature of these layers. Boron nitride nanotubes (BNNT) can be constructed in a transparent or translucent format that would provide an ideal cover material for solar panels that have significant ballistic performance, especially when combined with other layers of ballistic material.

In a second embodiment of the invention, the battery and/or energy generation layers would not be modified, but the properties of these electro active layers would be measured and incorporated into the overall ballistic strategy of the armour as outlined in the following section.

Armour is generally rated using a classification table that allows soldiers to quickly identify and select the appropriate plate rating for the situation they face. For example, the United States National Institute of Justice (NIJ) has published standards for ballistic protection, military standards MIL-STD-662F and STANAG 2920 are all examples of quantifiable standards which can be tested against. Higher levels of protection are generally considered safer, for example a Level III plate is rated to protect against a 9.6 gram NATO 7.62×51 mm rifle round, while Level IV will protect against armour piercing rifle rounds from a 10.8 gram 30-06 Springfield rifle round.

Armour must pass stringent ballistic testing and qualification in order to receive a rating under these standards. In order to achieve the level of protection listed on the plate, the soldier must use the armour in the proper way prescribed by the manufacturer. The armour plate construction therefore focuses on providing a complete solution to the soldier and this is most commonly done through a combined structure of multiple materials designed to reduce penetration, spread projectile force and ultimately protect the soldier. However, armour plates are designed and sold as armour, they are not designed to perform other functions required by the soldier.

In a preferred embodiment, the system would incorporate the measured and improved ballistic properties of the battery and/or energy harvesting layers (collectively the electro-active layers) into the armour layers in order to provide a hybrid electro active ballistic protection system.

Referring to FIG. 2, a very simplified ballistic armor solution (200) is shown. The projectile 201 hits the strike-face (202) of the armor system. The strike-face (202) may perform the function of shredding the projectile through the use of ceramics or another hard material. The capture layer (203) slows and stops the projectile pieces. This layer may deform considerably against the body and therefore a non-ballistic padding layer (204) may be included to cushion the entire plate against the body allowing the energy of the projectile to be spread over the body through compression of this layer. These three layers are being described in their most basic form, additional layers, functions, orders and properties may be used to achieve specific ballistic and comfort properties.

In the preferred embodiment may couple lower level armour layers, such as a light, thin and flexible Level II rated plate, with the electro active layers. The electro active layers would therefore not need to provide any ballistic protection on their own, but would be used to absorb and dissipate the energy of the projectile. In FIG. 2, this would effectively be achieved by replacing the padding layer (204) with flat battery cells. In this way, even a battery that is considered “soft” may still be combined in the armor system, without affecting the size, weight or ballistic rating for the total electro active ballistic system as the rated armour portion of the system would perform the task of stopping the projectile while the soft battery and/or energy harvesting portion of the system would provide the task of spreading force. The use of a battery layer with known or improved ballistic properties may allow the combined system to actually increase in overall ballistic rating, while at the same time maintaining the weight and size of the original plate system that did not store energy.

The order of layers may also be reversed or may be alternated or may be further combined. For example in another embodiment of the system, the battery would be formed in the outer layers of the electro active ballistic protection system. Referring again to FIG. 2, but in this case the projectile (201) would first strike the battery layer (202) and would be significantly slowed as it passed through this outer layer, which themselves may be enhanced beyond the normal ballistic properties of an off the shelf battery. When the projectile reaches the layers that are specifically focused on ballistic protection, for example a shredding layer (203) and stopping and/or padding layer (204), the remaining force of the projectile would be dissipated.

An alternating system of layers in another embodiment of the system would use a series of thin ballistic layers that may be composed of a high ballistic strength plastic material, inner layers that compose the battery system, a second ballistic layer of high strength plastic material, and finally layers of purely ballistic protection that may be composed of Kevlar® fibres, fibreglass, metal, ceramic, gel, variable durometer polymers, or other materials known to have good ballistic properties.

In the alternating system of layers, the high ballistic strength plastic can perform a dual function of housing the battery itself and in this way the battery may be constructed such that it is separable from the ballistic only protection plate. This simplifies removal of the battery for charging and removal, replacement or inspection of damaged ballistic plates.

In another embodiment of the system, material layers may be incorporated that have both piezoelectric and thermoelectric abilities in the same layer, with electricity collector plates formed in the shape of a wireless antenna receiver. In this way this single group of layers may perform thermal, kinetic and wireless harvesting simultaneously while also providing some level of ballistic improvement and protection.

The overall expectation of the electro active ballistic protection system is to provide a fully rated, ballistic protection solution that is of equal rating to its counterparts, while also providing energy storage (battery) and energy harvesting functions. In the above example, the preferred embodiment of the system may have the same size and weight as a Level III ballistic plate, and it would have the same ballistic rating of Level III, yet the preferred embodiment of the system would, in reality, be composed of a rated coupling of a Level II plate with ballistically matched and optimized electro active layers that work in conjunction with the armour plate in order to increase overall system ballistic rating.

The above description uses reference to specific protection levels for clarity. It would be well understood by someone trained in the art that similar embodiments of the invention could be constructed that would ballistically optimize the electro active layers and could allow an nearly infinite combination of ballistic ratings to be achieved that utilize a combination of single function energy storing or ballistic layers combined with a combination of multi-function layers that provide energy storage, energy harvesting and ballistic protection. The ability to store or generate electricity may also be seen as a reasonable trade-off against reduced ballistic protection whereby the user may be presented with a system of identical size and weight to their existing ballistic-only plate, but with a reduced ballistic rating, while including energy storage or harvesting. For example, the user may choose to replace a Level IV plate with a Level III plate where the Level III plate also includes a battery or energy harvesting function because the overall operational advantage of such a system outweighs the minor loss of ballistic protection rating 

What is claimed is:
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 5. A system for providing ballistic protection and storing electrical energy comprising a multilayer material configured to store electrical energy, comprising: i. a positive electrically-active layer having a positive charge; ii. a negative electrically-active layer having a negative charge; and iii. an insulating layer between the positive electrically-active layer and the negative electrically-active layer, wherein the multilayer material is configured to resist ballistics.
 6. The system of claim 5 wherein the positive electrically-active layer has a positive terminal and the negative electrically-active layer has a negative terminal.
 7. The system of claim 6 wherein the battery has a durometer of 110 or less and forms a soft layer of the material.
 8. The system of claim 5 wherein the electrical energy is stored as an electrochemical potential utilizing one or more elements selected from the group consisting of lithium, sulfur, cobalt, manganese, zinc, silver, cadmium and carbon.
 9. The system of claim 5 wherein at least one electrically-active layer has one or more additional ballistic materials added thereto, selected from the group consisting of micronized ceramics, single-walled nanotubes, electrically-conductive nanotubes and carbon nanotubes.
 10. The system of claim 5 wherein the insulating layer has one or more ballistic fibers therein, selected from the group consisting of Aramid, Kevlar, electrically-conductive nanotubes and boron nitride nanotubes.
 11. The system of claim 5 wherein the electrically-active layers are made of materials selected from the group consisting of copper alloys, aluminum alloys and carbon nanotubes for improved ballistic resistance.
 12. The system of claim 5 wherein the multilayer material harvests energy from kinetic energy through a means selected from the group consisting of the Seebeck effect, electrostatic generation, magnetic motion, Electro-active Polymers, nanogenerators and vibrational harvesters.
 13. The system of claim 12 wherein the insulating layer contains doped ceramic materials.
 14. The system of claim 5 wherein the multilayer material harvests energy from thermo-electric generation through an effect selected from the group consisting of the Ettingshausen effect, Nernst effect, Peltier effect, and Thomson effect.
 15. The system of claim 5 further comprising a receiver antenna connected to the multilayer material, the antenna configured to receive energy from electro-magnetic radiation, wherein the multilayer material stores the energy.
 16. The system of claim 5 wherein the multilayer material has an outer layer comprising one or more photovoltaic panels. 